Accompanying the release is the launch of Spark, a cute social game that's designed to fuel the adoption of Firefox 4 Mobile, much like last week's use of Glow and Twitter Party during Firefox 4 PC's release.

While the browser still feels a little rough around the edges, it's definitely worth trying out if you're still using Android's stock browser. Its JavaScript performance is significantly better than any other Android browser, and if you use Firefox on your PC, its built-in Sync functionality is awesome.

Over the next few days we'll have plenty of tips and tricks for Firefox 4 Mobile, and a list of the best add-ons available for the new browser.